1. Technical Field
The disclosure relates to a warning notification device, an electronic watch, a warning method and a recording medium configured to issue a warning of a surfacing speed during a diving.
2. Description of Related Art
In recent years, a wristwatch capable of being used underwater has been spread for marine sports such as scuba diving and a diving operation for performing an operation undersea or underwater. As the waterproof wristwatch for sports, a wristwatch having a pressure sensor embedded therein and configured to measure a water depth from a detected water pressure has been known.
In the meantime, during the diving, an inert gas such as nitrogen in the respiratory gas is dissolved in the body by a high pressure due to a water pressure. For this reason, it is necessary to take a sufficient rest time so that the inert gas accumulated in the body is completely discharged after the surfacing.
Also, since the excessive surfacing speed is a greatest factor causing the dysbarism, it is necessary to take measures so that the surfacing speed does not exceed a predetermined surfacing speed.
In an information processing device for a diver disclosed in Patent Document 1, which is configured to be useable with being attached to an arm, a water depth is detected by an embedded pressure sensor, a nitrogen partial pressure of the respiratory gas during the diving is calculated on the basis of the detection and an amount of nitrogen in the body is simulated from the nitrogen partial pressure of the respiratory gas and the diving time, so that a time (no-decompression divable time) until the nitrogen partial pressure reaches an allowable value of the nitrogen partial pressure in the body at any water depth and a time (body nitrogen discharge time) until the nitrogen partial pressure in the body is lowered to an equilibrium value over the water are obtained.
Thereby, even when a diver does not take the rest time enough for the inert gas excessively accumulated in the body to be completely discharged on shore, it is possible to report information for safe diving to the diver in advance.
Also, for example, a Japanese Patent Application Publication No. Hei 11-23747A discloses that the current surfacing speed is obtained every six seconds, the surfacing speed and an allowable value of the surfacing speed corresponding to a current water depth are compared, and when the surfacing speed is greater than the allowable value of the surfacing speed, a warning is issued.
In the meantime, Article 18, Paragraph 1(1) of the Ordinance on safety and health of work under high pressure referred to for the diving operation prescribes “the decompression speed should be equal to or less than 0.08 mega pascal every minute.” When the decompression speed (surfacing speed) is set to 10 m per minute, it becomes 0.17 m per second.
According to the technology disclosed in Patent Document 1, it is possible to determine the surfacing speed in correspondence to the water depth. However, when the diver wears the wristwatch configured to measure the water depth on the arm, a measurement error of the water depth occurs due to an up-and-down movement of the diver's arm during the surfacing.
More specifically, the surfacing speed exceeds the allowable value of the surfacing speed by the movement of moving the arms upward for a short time (for example, 2 to 3 seconds). To the contrary, a diving state may be erroneously detected by the movement of moving the arms downward during the surfacing.
In order to prevent the measurement error of the water depth due to the movement of the diver's arms, it is considered to reduce an error due to the movement of the diver's arms by prolonging the measurement time period. In this case, however, the determination is delayed.